Archive for the 'science' Category

There’s a great article in the NY Times about tool-making by crows. It includes a link to a really interesting short video. Pretty remarkable what these birds can do with a small brain. And it’s not instinctive, either — I mean, we all know tiny-brained birds can make amazing nests by just following some rules. But these crows actually figure stuff out. I’ve blogged about this before, if you want to search the archives.

Golden Gate Audubon Society just put up an information page about how many birds are killed in collisions. The uncertainties are pretty high, but even the low-end estimates are huge: at least 100 million birds per year killed in collisions with windows, for example. A lot of these happen one collision at a time — a bird gets hit by a car, or runs into a window that it doesn’t realize is there. But sometimes there are horrific mass-kill incidents, when huge flocks of birds get confused by radio tower lights and fly in circles around them, with birds running into the guy wires at every circuit and falling to the ground with wings broken. There are known things that can be done to reduce all of these causes of mortality, if we can get people to care.

The IBRRC is, of course, totally overwhelmed with birds from the gulf oil spill. They work in many other places too. They’ve done a lot of great work over the years, both developing better treatment and cleaning methods and actually saving birds. They could really use your contribution, now or any time: go to their blog and hit “Donate Now.”

BBN News has a story about a recent article in the medical journal “The Lancet.” It says:

When the records of more than 366,000 people who died between 2001 and 2005 were analysed, it revealed that even tiny green spaces in the areas in which they lived made a big difference to their risk of fatal diseases.
Although the effect was greatest for those living surrounded by the most greenery, with the “health gap” roughly halved compared with those with the fewest green spaces around them, there was still a noticeable difference.

Back in January, I blogged about how and why the south Asian white-backed vulture is on its way to extinction: a medicine called diclofenac, given to cows in India, is so toxic to vultures that a few bites from a dead cow will kill the vulture. In just a few years, vultures have gone from ubiquitous to nearly extinct. Some scientists have started captive breeding programs to save the species, in the hope of releasing them to the wild in the future. (Diclofenac is officially banned but is still being made and used).

While the death of an unattractive bird that scavenges for a living may not sound like a great loss, vultures have important cultural and religious significance in south Asia. The ancient Parsi religion holds earth, fire and water sacred, and to avoid contaminating them, the Parsis dispose of their dead by placing them on “Towers of Silence,” where vultures consume the remains. In addition, the vulture saint Jatayu is an important figure in Hindu religion. The absence of vultures poses a direct threat to public health as well, as uneaten livestock carcasses provide breeding grounds for bacteria and attract feral dogs, which may spread rabies and other diseases.

ScienceDaily reports: “Large flightless birds of the southern continents – African ostriches, Australian emus and cassowaries, South American rheas and the New Zealand kiwi – do not share a common flightless ancestor as once believed. Instead, each species individually lost its flight after diverging from ancestors that did have the ability to fly, according to new research conducted in part by University of Florida zoology professor Edward Braun.”

I’m surprised that they’re surprised! Well, OK, they’re maybe not “surprised,” I guess the data are ambiguous and now the evidence leans the other way from what they previously thought.

Whatever. At any rate it looks like the similarities of these birds are due to “convergent evolution” rather than the geographic distribution of a single type of bird.

The New York Times has an article about recent research by John M. Marzluff, who studied whether birds can recognize people’s faces.

To test the birds’ recognition of faces separately from that of clothing, gait and other individual human characteristics, Dr. Marzluff and two students wore rubber masks. He designated a caveman mask as “dangerous” and, in a deliberate gesture of civic generosity, a Dick Cheney mask as “neutral.” Researchers in the dangerous mask then trapped and banded seven crows on the university’s campus in Seattle.

In the months that followed, the researchers and volunteers donned the masks on campus, this time walking prescribed routes and not bothering crows.

The crows had not forgotten. They scolded people in the dangerous mask significantly more than they did before they were trapped, even when the mask was disguised with a hat or worn upside down. The neutral mask provoked little reaction. The effect has not only persisted, but also multiplied over the past two years. Wearing the dangerous mask on one recent walk through campus, Dr. Marzluff said, he was scolded by 47 of the 53 crows he encountered, many more than had experienced or witnessed the initial trapping. The researchers hypothesize that crows learn to recognize threatening humans from both parents and others in their flock.